Comparison of performance of Chirobiotic T, T2 and TAG columns in the separation of beta2- and beta3-homoamino acids.
The enantiomers of eight unusual beta(2)- and beta(3)-homoamino acids were separated on chiral stationary phases containing the macrocyclic glycopeptide antibiotic teicoplanin (Chirobiotic T or T2) or teicoplanin aglycone (Chirobiotic TAG) as chiral selectors. The effects of the organic modifier, the mobile phase composition, and temperature on the separations were investigated. Linear van't Hoff plots were observed in the studied temperature range, 280-318 K, and the changes in enthalpy, Delta(DeltaH(o)), entropy, Delta(DeltaS(o)), and free energy, Delta(DeltaG(o)) were calculated. The values of the thermodynamic parameters depended on the nature of the selectors, the structures of the analytes, and especially the positions of the substituents on the analytes. A comparison of the separation performances of the macrocyclic glycopeptide stationary phases revealed that the Chirobiotic TAG column exhibited much better selectivity for beta(2)-homoamino acids, while the separation of beta(3)-homoamino acid enantiomers was better on Chirobiotic T or T2. The elution sequence was determined in some cases and was observed to be R < S.
Pataj
Zoltán
Z
Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged, Hungary.
Ilisz
István
I
Berkecz
Robert
R
Misicka
Aleksandra
A
Tymecka
Dagmara
D
Fülöp
Ferenc
F
Armstrong
Daniel W
DW
Péter
Antal
A
D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification*; D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation* / Q000379:methods; D015394:Molecular Structure; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics
D000596:Amino Acids; D002021:Buffers